Usage of a phrase: "like hell"

Solution 1:

The comma breaks the meaning up, as you've described.

"Like hell, I'll be there" would indicate that you will be at a specific place, just as hell will also be at that place. This phrase with the commas is not idiomatic in writing or speech.

"Like hell I'll be there" would emphatically deny that you will be at a specific location. This is the normal usage found in writing and speech. See it in the Idiom dictionary

As in all languages, context is everything. And in modern typing, commas are not to be trusted.

So, if you wrote an email to your boss and said "Will you be at the IT meeting?" and he replied, "Like hell, I'll be there," you'd want to know how well your boss gets along with IT before making an assumption about what he meant by his email. The comma is not normally associated with the phrase and it could have easily been placed due to sloppy punctuation.